The melee generally won't line of sight you either often making them the better choice but again it is a match by match thing.

Can I just add though, please please PLEASE!! keep hitting the same target. I play ranged and it drives me absolutely nuts the amount of melee who switch targets every 6 seconds and then get angry when we lose. We need to focus on one target to burst them down then move on to the next. You aren't 'pressuring the healer' or whatever you think you are doing. A good healer can triage multiple targets. You are just gimping your rotation and mine, maximum damage depends on debuffs and dot's which generally take time to apply and build up.